Oil burner



F. HARDINGE ET AL 1,707,761

OIL BURNER Fild May 5, 3

April 2, 1929.

Patented Apr. 2, 1929.

. UNITED STATES PATENT OFFICE.

FRANKLIN HARDINGE AND BENJAMIN H. CONNOR, OF CHICAGO, ILLINOIS,ASSIGNORS TO HARDINGE BROTHERS, INC., OF CHICAGO, ILLINOIS, ACORPORATION OF ILLINOIS.

OIL BURNER.

Application filed May 5,

Our invention relates to improvements in oil burners, and isparticularly concerned with, though not limited to, improvements in thattype of oil burner embodying a rotary atomizing or forming the oil in afine spray which is subsequently mixed with the proper amount of air forcombustion.

Heretofore, in the operation of burners of this type, considerabledifficulty has been experienced by the formation of carbonaceousdeposits upon the bottom and walls of the fire box due to the incompletecombustion of the fuel itself, and to the fact that the oil was notcompletely atomized before it struck the walls of the fire box. If adepositof this character once starts to build up, it usually continuesuntil it seriously interferes with the operation of the burner, andrequires shutting down the burneruntil the deposit can be removed. Thisis a rather difiicult matter and has always been a source ofconsiderable expense in the maintenance of burners of this type.

The objects of our invention are to provide means co-operating with theatomizer in such manner as to direct the air currents, to be mixed withthe atomized fuel, away from the walls, and particularly from the bottomof the fire box, so as to thoroughly atomize the fuel and mix it withthe air to form a completely combustible mixture before the oil has hada chance to contact with and become deposited upon the walls of the firebox. Y

Another object of our invention is to provide means, such as described,which will permit easy and accurate adjustment of the supply of air.

A further object of our invention is to provide means, such asdescribed, which will not be rendered inoperative by thedeposit ofcarbon upon the means itself.

A still further object of our invention is to provide means, of thecharacter described, which is simple in construction and economical tomanufacture.

Other objects of our invention will appear as this descriptionprogresses, reference being had to the accompanying drawing, which showsour invention embodied in an oil burner shown in central verticalsection,

driven by the bevel pinion 7 and the bevel gear 8. The bevel gear 8 isdriven by a motor, not shown, through the shaft 9. A tubular outwardlyflaring atomizing nozzle 10 is secured to the upper end of the spindle6, and the flaring portion thereof carries a; plurality of radiallyextending fan blades 11 for supplying air to the oil spray dischargedfrom the atomizing edge 12 of the atomizer.

A stand pipe .13, extending upwardly through the hollow spindle 6 andsupplied with oil by the pipe 14, is provided at its upper end. withdownwardly directed discharge tubes 15 which discharge the oil into theannular space 17 formed between the upper end of the spindle and thethimble 18. When the atomizer is rotated, the oil discharge into thisannular space moves upwardly under centrifugal force along the innersurface of the atomizer, and is discharged from the edge 12 in a finespray.

To render this fine spray completely combustible, it is necessary to mixit with the proper quantity of air, and for this purpose we provide theneck ring 19 which pro ects through the bottom 20 of the fire box, whichis preferably formed of fire clay. A plurality of rollers 21 aresupported by the neck ring 19, only one being shown in the present case.A sleeve 22 isprovided with inclined cam faces 23 which rest upon therollers 21 so that when the sleeve 22 is rotated by any suitable means,such, for instance, as a link 24, the inner end of which is secured to apin 25 projecting downwardly from the sleeve 22, the sleeve will bevertically adjusted. The upper edge of the sleeve 22 is provided with aplurality of equally spaced opening 30 slightl larger in diameter thanthe fan blades. 11 annular depression 31 is formed in the upper face ofthe ring 29, the radius 9" of this depression being substantially equalto the diameter d of the atomizer at its atomizing edge. \Ve have foundthat when the diameter d of the annular depression 31 is made less thantwice the diameter (Z of the atomizing nozzle, it

functions better than when this ratio is increased. We have found thatthis diameter d varies from 6 for an atomizer having a diameter at equalto 3", to 7 A for an atomizer having a diameter d equal to 4". l/Vherethe latter diameter is equal to 3 we have found that the diameter (ishould be approximately 6 ,4 The depth d" of the depression varies withthe diameter of the atomizer, being larger for small atomizers than forlarger atomizers. Our experiments have demonstrated that for an atomizer3" in diameter, this distance should be approximately for an atomizer 3in diameter, and for an atomizer 4" in diameter,

Experiments have demonstratedthat the shape of the periphery 29 has animportant bearing upon the direction of air currents after they leavethe controlling ring, and that if the edge of this ring is madevertical, the flame has a tendency to swirl down into contact with thebottom 20 of the fire box, depositing carbon thereon. After numerousexperiments, we have found that the best results are obtained bybeveling the edge of the ring, as shown at 32. This bevel becomessmaller with increase in diameter of the ring, the angle a beingapproximately 30 for a 3 burner, 25 for a 3 burner, and 20 for a 4burner, this angle becoming still less as the diameter of the burnerincreases. I

We have found through experiment that if the ring 29 is adjusted so thatthe edge 33, formed by the annular depression 31 and the bevel 32, isapproximately in the same plane as the atomizing edge of the atomizer,considerable variation in the quantity of fuel or oil supply to theatomizer may be made without varying the adjustment of the sleeve 22. Atthis point, the upper edge of the neck ring 19 has uncovered a portionof the notches 26 in the sleeve 22, thereby permit-ting air to flowthrough these notches and mix with the mixture previously formed by theatomized fuel and the air discharged from the fan blades 11. Apparently,the amount of fuel burned automatically controls the natural draftthrough the notches 26 so as to maintain substantially the correctproportion between the oil and the air.

For the purpose of centering the air controlling ring. upon the sleeve22, we provide the lower face thereof with the downwardly extendingbeveled ring 34, which rests upon the beveled faces 28 of the teeth 27.lVe also prefer to undercut the under surface of the ring, as shown at35, to prevent oil from creeping ba'ek and dropping through the neckring.

\Ve have found the above construction very eflicient in preventing thedeposit of cal-ion upon the bottom and walls of the tire box,particularly if the inner end of the atomizer is elevated slightly abovethe bottom of the fire box. lVehave also found that a ring, having theconstruction described above, will remain in operation over veryextended periods of time without having carbon deposits formed thereon,and that the contour of this ring is such as to assure very completemixture of the air and fuel so that the fuel is practically completelyburned.

While we have shown the details of the preferred embodiment of ourinvention, it is to be clearly understood that our invention is notlimited to these details of construction, and it is also to beunderstood that our invention is not limited to use with an atomizer ofthe construction shown in the accompanying drawing, but may be used withan atomizer in which separate means are employed for supplying airthereto. Other adaptations and modifications of our invention within thescope of the appended claims will occur to those skilled in this art.

Having thus described our invention, what we claim is:

1. The combination with a rotary tubular shaped outwardly, flaringatomizer having radially extending fan blades carried by the outwardlyflaring portion thereof, of means for controlling the supply of air tothe oil spray formed by said atomizer comprising a neck ring surroundingsaid atomizer and spaced therefrom, a sleeve adjustably mounted in saidneck ring, the upper edge of said sleeve being, notched to provide aplurality of spaced teeth, the inner edges of which are beveledoutwardly, and an air controlling ring having a substantially flat undersurface provided with an annular beveled rib for resting upon thebeveled surfaces of said teeth, the opening in said ring being slightlylarger than the diameter of said fan blades, the upper face of said ringhaving an annular depression formed therein, the inner edge of which islower than the outer edge, the radius of the curvature of saiddepression being substantially equal to the diameter of said atomizer atits atomizing edge and the outer diameter of said depression being butslightly less than twice said diameter of said atomizer, said ring beingbeveled outwardly and downwardly from the outer edge of said depression.

2. The combination with a rotary tubular shaped outwardly flaringatomizer having fan blades carried by the outwardly flaring portionthereof, of means for controlling the supply of air to the oil sprayformed by said atomizer comprising a; neck ring surrounding saidatomizer and spaced therefrom, a sleeve adjustably mounted in said neckring, and an air controlling ring having a substantially flat undersurface resting upon said sleeve, the opening n sald ring being slightlylarger than the diameter of said fan blades, the upper face of said ringhaving a broad annular depression formed therein, the inner edge ofwhich is lower than the outer edge, the radius of the curvature of saiddepression being substantially equal to the diameter of said atomizer atits atomizing edge the outer edge of the depression being at asubstantial distance outwardly from the nozzle.

3. The combination with a rotary tubular shaped outwardly flaringatomizer and means for supplying air thereto, of means for controllingthe supply of air to the oil spray formed by said atomizer comprising anair controlling ring having an 0 ening therein, the upper face of saidring aving an annular depression formed therein, the outer edge of whichis higher than the inner edge and is at substantially the level of thedischarge edge of the nozzle, the radius of the curvature of said deression being substantially equal to the diameter of said atomizer atits atomizing edge, and the outer diameter of said depression being at aspaced distance outwardly from the discharge edge of the nozzle.

4. The combination with a tubular shaped outwardly flaring atomizerhaving fan blades carried by the outwardly flaring portion thereof, ofmeans for controlling the supply of air to the oil spray formed by saidatomizer comprisinga ring surrounding said atomizer in spaced'relationto said fan blades, said ring having a depression formed in its uppersurface for directing the air discharged from said fan blades upwardlyand into the oil spray formed by said atomizer at points lying on acircle, the diameter of which is somewhat less than twice the diameterof said atomizer at its atomizing dge.

5. The combination with a fire box having an opening formed in one wallthereof, of a rotary atomizer extending through said opening, means forsupplying air to the spray formed by said atomizer, and means fordirecting said air into said spray and for preventing said spray fromcontacting with said wall comprising a ring surrounding the inner end ofsaid atomizing nozzle and having a depression formed therein, saiddepression flaring outwardly and upwardly to discharge the air into thespray at a spaced distance outwardly from its discharge from the nozzle.

6. A fuel oil burner comprising, in combinat-ion, an outwardly flaringrotary atomizing nozzle, an air ring disposed around the nozzle at itsdischarge end, means for creating an outward flow of air between thering and the nozzle, the upper surface of the ring adjacent the nozzleextending outwardly at level below the discharge edge of the nozzle tocarry the air flow horizontally outwardly beneath the oil spray from thenozzle but,

at a spaced distance outwardly from the discharge edge of the atomizer,curving upwardly to an annular ridge at a height substantially at thelevel of the discharge edge of the nozzle to direct the air flow intothe spray at a point where the spray has been thinned by its increasingcircumference, for lifting the oil film.

7. A fuel oil burner comprising, in com bination, an outwardly flaringrotary atomizing nozzle, an air ring surrounding the discharge endthereof, and means for inducing an air flow between the nozzle and thering, the ring having a broad upper surface for carr ing the air flowhorizontally outwardly rom the discharge edge of the nozzle below andsubstantially parallel with the oil spray therefrom and, at a spaceddistance outwardly from the discharge edge, having'an upwardly inclinedcontour for directing the air flow upwardly into the oil spray.

8. In an oil burner, the combination of a rotary atomizing nozzlethrowing off a spray of fuel oil under centrifugal force from itsdischarge edge, an air ring disposed around the discharge end of thenozzle, means for creating a forced flow of air between the ring and thenozzle, the ring extending horizontally outwardly below the dischargeedge of the nozzle and being curved upwardly at its outer edge to form aridge approximately at the level of the discharge edge but spacedoutwardly therefrom for directing the air into the spray at the regionof the ridge.

9. In an oil burner, the combination of a rotary atomizing nozzlethrowing ofl a spray of fuelvoil under centrifugal force from itsdischarge edge, an air ring disposed around the discharge end of thenozzle,-means for creating a forced flow of air between the ring and thenozzle, the ring extending horizontally outwardly below the dischargeedge of the nozzle and being curved upwardly at its outer edge to form aridge approximately at the level of the discharge edge but spacedoutwardly therefrom for directing the air into the spray at the regionof the ridge, the air ring beyond said ridge being beveled downwardlyfor directing backward eddy currents of air upwardly into the spray atthe region of the ridge.

10. An oil burner comprising an annular rin a rotary atomizing nozzledischargin a or spray of oil under centrifug force, means for forcing acurrent-of air between the nozzle and the ring, the ring having a broadupper surface for carrying the air current horizontally outwardlybeneath the oil spray and in direct contact with the under side thereof,said surface of a fllm or spray of oil under centrifugal force,

after leaving the means for forcing a current of air between the nozzleand the ring, the ring having a broad upper surface for carrying the aircurrent horizontally outwardly beneath the oil spray and in directcontact with the under side thereof, said surface of the ring beingcurved upwardly about its outer edge to direct the air current into theoil spray at a region spaced outwardly beyond the discharge edge of thenozzle but slightly less than the radius of the discharge edge of thenozzle.

12. An oil burner comprising, in combination, a tubular outwardlyflaring rotary at-omizing nozzle, fan blades on the exterior of thenozzle beneath the flaring mouth thereof, a neck ring formin r thecentral margin of an annular firebed: an air ring disposed about thenozzle andsupported on the neck ring and vertically adjustablerelatively to the fan blades whereby a greater or smaller portion of theair current created by the fan blades may be discharged onto the topsurface of the ring, the ring havim a broad surface extending outwardlybeyond the discharge edge of the nozzle for carrying the air currenthorizontally outwardly beneath the oil spray and radially beyond saidsurface having an upwardly contoured surface for then directing the aircurrent upwardly into the oil spray after the spray has been thinned by,its increased radius discharge edge of the nozzle.

13. An oil burner comprising, in combination, a firebed having a centralopening, a rotary atomizing nozzle extending therethrough fordischarging an annular spray of oil across the bed, an air ring disposedaround the nozzle at its discharge end, means for creating a forced airdraft between the nozzle and the ring, the upper surface of the ringhaving a broad, horizontal annular surface about the nozzle and radiallythere beyond having an upwardly inclined annular surface to carry theforced air outwardly and then upwardly into the oil spray, means foradmitting a natural draft beyond the outer edge of the ring forsupplying addi tional air to the mixed oil and air and for keeping thefire and oil off the bottom of the firebed.

.tally disposed fire pot having 14. An oil burner comprising, incombination, a firebed having a central opening, a rotary atomizingnozzle extending therethrough for discharging an annular spray of oilacross the bed, an air ring disposed around the nozzle at its dischargeend, means for creating a forced air draft between the nozzle and thering, the upper surface of the ring having a broad, horizontal annularsurface about the nozzle and radially there beyond having an upwardlyinclined annular surface to carry the forced air outwardly and thenupwardly into the oil spray, means forming air passages for a naturaldraft leading into the region above the firebed beyond the outer edge ofthe air ring, and closures for said passages, the air ring beingvertically adjustable for increasing or diminishing the volume of forceddraft directed across the air ring and the closures being connected withthe ring for opening the passages when the ring is moved to a positionof diminished forced draft.

15. An oil burner comprising a horizona central opening, verticallyjournaled tu ular outwardly flaring rotary atomizer, protruding throughthe central opening of the fire pot, radial fan vanes carried on theunder side of the lip of the atomizer for generating a substantiallyhorizontal outward flow of air from beneath the oil film discharged bythe atomizer, an air ring covering said opening, the inner edge of theair ring forming with the lip of the atomizer a discharge constrictionfor the primary air supply from the fan vanes, and the outer edge of thering forming with the inner edge of the fire pot a passageway for asecondary supply of air by suction or gravity, the upper surface of thering at its outer region being inclined downwardly to its outer edge tocause a portion of the primary air flow to hug the floor of the fire potwhereby the aspirating effect of the lower strata of the primary airflow aspirates the secondary air flow through its said passage.

16. An oil burner comprising a fire pot forming the bottom of acombustion chamber and having a central opening, a vertically journaledrotary centrifugal atomizer having an outwardly-flaring discharge endprotruding through the opening in the tire pot and carrying radial 'fanvanes beneath the discharge lip for generating a substantiallyhorizontal outward flow of air, a ring surrounding the atomizer beneathits lip, the air flow being directed over the upper surface of the ring,the upper surface of the ring at its outer edge being downwardlyinclined, and an auxiliary air inlet passage formed between the outerlower edge of the ring and the fire pot.

17. A fuel oil burner comprising a vertically journaled rotarycentrifugal atomizer horizontally discharging a spray of oil,centrifugal fan vanes below the discharge edge of the atomizer forsupplying a horizontal air current beneath and in contact with the oilspray, and an annular air directing ring surrounding the atomizer belowthe discharge edge, and forming an air discharge opening between it andthe discharge edge, the upper surface of the ring being annular-1yprofiled to provide a relatively broad outward air directing surfaceand, at an annular region radially beyond the discharge edge of theatomizer, curving upwardly and outwardly to lift the air current.

In Witness whereof, we hereunto subscribe our names this 21st day ofApril, 1923.

FRANKLIN HARDINGE. BENJAMIN H. CONNOR.

